Almost all passenger transport vehicles have interior lights. Such lights are on the one hand provided for the general illumination of the vehicle. On the other hand, they are provided for signalling purposes to the passengers. In the example of an aircraft, such signalling lights may be used for emergency lighting and other purposes. For both of these application scenarios, LED light units are becoming more and more common. Also, light units exist that have LED's of various colors. This allows for illumination in different colors at different points in time and/or color mixing for reaching a desired shade of a particular color.
The power conditioning in current LED light units with multiple color LED's is not satisfactory. LED light units commonly need some form of power conditioning to transform the power received from a power supply, such as an on board power supply network in the case of an aircraft, into power suitable to drive the LED's. Previous approaches of power conversion either suffered from large complexity or generated undesirable amounts of heat.
Accordingly, it would be beneficial to provide a multi-color light unit that allows for a reduction in heat generation in the power conditioning portion, while at the same time allowing for low complexity thereof. Further, it would be beneficial to provide a passenger transport vehicle with such improved multi-color light unit.